When to Start Gardening Seeds Indoors

The delicious veggies from your own garden just have this inexplicably elevated taste and flavor, not to mention how sure you are of the quality. It’s not only fresh, but it’s also an incredibly rewarding feeling; watching those seeds planted by your hands sprout into beautiful, healthy plants that feed you and your family. Gardening has so many benefits and only a few key tools you need. However, with every other aspect of life, there’s a learning curve, and you won’t be able to strike the right cord without some trials and errors. These green thumbs all over the internet that are growing some impressive veggies in their windowsill didn’t get there in one day, so you won’t too – and that’s okay! 

For a beginner, starting with seeds presents a myriad of challenges and tons of learning opportunities. Starting seeds properly is the deciding factor of your whole growing season. From soil to other factors, there’s alot to decide. If the timing is right and your efforts are there, you’ll end up with your envisioned garden. 

For the gardening enthusiasts that are struggling to find a starting point, we present our guide to help you grow into a master farmer. Here’s everything to be aware of when starting growing seeds for indoor gardening.

greenhouse plants
Greenhouse Plants

Indoor Gardening 101

Forget the pots. Stop overthinking about the kind of compost you should use. Everything must start from a ground zero – a calendar in this case. Multiple regions only have some months when they don’t see frost, so understanding the climate and opportunity for growth is the primary step.

Why Begin from Seeds?

Many people choose to buy saplings from commercial outlets instead of starting veggies from seed. While it’s a fine thing to do and quite common, there are some convincing reasons why you should opt to start your plants. The first can save you a few headaches later on, but the latter is a more fulfilling experience, as stated by many gardening masters.

For the most part, starting seeds is done to get a kick start from the gardening season. In places where the growing seasons are short, starting seeds give you an added few weeks of growth time, which can be a big redeeming factor when the first air of frost season arrives in the fall. These plants need to be big enough to transplant outside during their usual plantation time. You need to know when to start your seeds indoors and eventually transplant them outdoors to boost your harvest. 

In contrast, warmer seasons do have it easier. Starting seeds indoors allows you an additional round of harvest (specifically cool-climate crops) before the summer heat looms in and minimizes growth. 

Also, if you want a bigger garden, i.e., a ton of plant, seeds are definitely going to be the cheaper option in comparison to individual purchases of saplings from the nursery. There’s also the factor of quality. Some nursery plants grow like a dream, while others are sub-par to the say the least. You have much better control over how the seedlings are nurtured when you plant your own seeds. If you’re an organic gardener, this is quite crucial.

Lastly, you won’t always find an impressive variety of plants up for sale at the local nurseries. Planting from seeds opens you up to a greater selection of tastes, textures, shapes, and what not! You can experiment with newer seeds too. 

What Month Do You Start Seeds Indoors?

The instructions will tend to vary on seeds, but the general rule of the thumb suggests the start of sowing seeds indoor should happen 6 to 8 weeks prior to the last frost date.

Here are three dates/terms you should know to assist you on your journey to start indoor farming:

Frost Date – The day of the year when there’s almost 50% possibility that the temperature will fall under freezing point, resulting in frost forming on the ground. In fall, there’s a “first frost date” while in spring, there’s a “last frost date.” 

Last Frost Date – On average, the last date in spring where there was a killing frost. High chance of death of plants planted before that date. Seeds in the ground should be safe unless if it’s a very solid freeze, or the ground freezes as well.  It also decided the germination date of the first seeds, and whether or not it will actually happen. Frosty nights of spring are too cold for some kinds of vegetables to resist.

Additionally, the last frost date will also determine which veggies you can plant. Generally, spring produce like spinach, lettuce, cabbage, beets, radishes, and carrots are on the hardier side and able to take more than 32 degrees. Tomatoes, cucumbers, peppers, and other warm-season crops can’t really make it through the cooler temperatures persisting at the beginning of spring in most environments. If you want to cultivate these garden favorites, it’s highly recommended that you wait till the temperature hits 55 degrees and above in your region. 

Growing Time – The average count of weeks between plantation and transplantation of seeds. Every vegetable varies in the growing season. Check your seed packet for the most accurate information. 

Planting Time – Cool-season veggies can live outside for a maximum of 4 weeks prior to the last frost while warm-season veggies can’t travel the distance till after the final frost date.

It’s notable that there’s no sure shot way to predict the date of the last frost, so if you’ve already transplanted your seeds outside but fear a frost settling in, prepare your mulch and plastic!

Seed packets, cultural information, and nursery tags tend to provide general planting guidelines after roughly assuming the last frost date. As we’ve said multiple times, be aware of your climate to know what your garden can be composed of. Never start your tomato seeds too early. Always make sure to wait till six weeks before the final frost date on this one.

What Vegetables Should Be Started Indoors?

Seeds and crops can be divided into three categories based on the plantation place: Indoors, outdoors, and variable. Gardeners living in warmer climates can start more seeds inside in comparison to the ones living in colder zones. 

With that being said, the list about what you can start indoors and outdoors isn’t clad on stone; it differs by your location, experience, as well as the crop itself.

It’s important to note how the types of vegetable grow and how they vary from each other. For instance, beets and carrots (a root vegetable) can’t deal with their roots being maneuvered, so it’s best to start them outside in the ground rather than having them go through transplantation later on. On the other hand, vegetables like peppers and tomatoes are very vulnerable to the cold weather of spring. Thus, it’s only wise to start them indoors and protect them from the breezy winds. Last but not least, plants like peas grow fast and are tolerant of the cold, making them a good choice for outdoor plantation. 

Start Indoors – Brussels Sprouts, Cauliflower, Broccoli, Cabbage, Lettuce, Eggplant, Pumpkins, Swiss Chard, Peppers, Tomatoes, Watermelons.

Start Outdoors – Carrots, Garlic, Beets, Okra, Onions, Parsnips, Corn, Radishes, Sweet Potatoes, Squash/Zucchini, Potatoes.

Variable – Celery, Kale, Beans, Spinach.

Make sure to pick up indoor seeds that align to what you want to grow above. 

Checklist Before You Start Seeding Indoors

  • Brush up on your seed knowledge: Get seed catalogs from multiple brands and compare them for pricings and offerings. There’s a chance that your regional companies will display an improved variety of crops that are better suited to your location.
  • List everything you’d like to grow: Before anything, you need a dream, right? Here it’s a list of what you’d like to plant. Imagine your garden ¼ the original size. This upgrades spacing practices.
  • Grow light for late winter: Consider getting a grow late if you’re starting in the later weeks of winter. Majority of the veggies will require at least anywhere from 6 to 8 hours of direct sunlight, so it’s great to have a grow light for the later days of winter. These lights will come to be very useful in preventing your plants from getting excessively leggy.
  • Accept there might be some losses: Although it’s recommended that you don’t overdo it with the plantation for your garden space, do remember that not all of your seeds will germinate, or they might die for unknown reasons later on. Do plant a few extras, but not too many.
  • Use clean containers: You’ll get peat pots, seedling flats, or other growing pots from most seed catalogs, but egg cartons act just as well as any other container in the primary stages of seed starting. Make sure you’ve poked holes along the sides of the bottom edge of the used containers in order to promote drainage of additional water. Understand you may need to transplant these seedlings into bigger containers even before transplanting them outside into the garden.
  • Label the containers properly: It’s super annoying to forget what you planted, especially when you’re experimenting with a variety of similar plants. So don’t forget to label your containers.

Introduction to Seed Starting

Now that you know the requirements to start seeding indoors let’s learn how to actually go through the process.

Using the Perfect Growing Medium

It goes without saying that seedlings are extremely delicate. To increase the chances of success, start the seeding in a sterile, fresh seed-starting mix that’s fluffy and light and created to retain just the right amount of moisture. If the growing medium isn’t sterile or is too wet, your seedlings may contract deathly diseases. If it’s excessively sticky or heavy, new fine roots won’t be able to penetrate and go through.

Selecting the Appropriate Container for Indoor Sowing

Any container that properly accommodates the growing medium and features holes for drainage will do fine, but we do recommend using premium designed seed starting kits as there’s everything included that makes healthy, strong seedling. 

If you don’t want to use the kits, you can always buy biodegradable pots that disintegrate in the soil. You can directly set them in the garden, thus, avoiding disrupting the young plant’s roots’ growth. Some are created of organic peat or fiber. You could also DIY one from a newspaper. However, these aren’t the same as biodegradable resin pots that fall apart in a landfill or maybe a compost heap lastly. These can’t be planted directly in the garden. 

How Much Light Does It Need?

These baby plants need a lot of sunlight to support their feeble and spindly bodies. An adequately sunny window (facing the south) would do good for a number of plants given you’re not located too far from the north, but using artificial plant lights give you that boost. Your plants will get light they need even on days when the sun is shrouded in clouds and shorter days of winter. You can choose from a wide range of options in the market. Make sure to get one where the height can be adjusted and something that offers a broad spectrum of light rays.

Consider setting a timer as it can be useful in reminding you to switch the lights on and off. This way, your plants will get the 16 hours of light they require each day, and also a comfy rest when the sun goes down (or, the light is off). Set the lights about 3 to 4 inches over the plants.

How Much Warmth Do Your Seeds Require?

There are two stages in the seed-starting process: germination and growing. The sprouting stage is termed as germination when the leaves and roots emerge from the seedling. There’s no need for added light at this point because it takes place under the soil, but there’s a need for subtle warmth, nothing too harsh. You can use heat mats to supply this heat to your plants, and they come in tons of sizes that are available all over the market. To promote germination, the best ones set the temperature 10-degree F warmer than the surrounding temperature. Eyeball the size and once the sprouts reach half an inch in height, get plant lights. If the room temperature is ranging between to 60 to 70 degrees F, you can get rid of the heat mats. 

How Much Water Should I Feed the Seeds?

Much like humans, plants are mainly composed of water, but their ratio is much higher. This keeps them turgid; plus, the water is need for photosynthesis which supplies them with the energy needed to grow. Water is the element that starts the process of germination. However, be careful with the amount of water you’re sprinkling over your plants because overwatering is a much more common incident than what we would like. Seedling failure is a result of this phenomena. 

The pre-moistened mix plays an incredibly important role in the overall growth of the plant, not to mention the chances of survival. Sow your seeds when it’s just moist but not drenched with moisture. Close the container with a cover from the kit, or you could also use a clear plastic wrap to capture the humidity – this helps germination. Do leave some space out for air circulation. 

After they’ve sprouted, remove the cover/wrap and water them by pouring it into the trays slowly. Ensure there’s free air circulation, so there’s no trapped humidity around the plants.

How Frequently Do I Inspect My Indoor Seeds? 

Do you know what the secret is to successful seed-starting? The answer might surprise you.

If you thought checking up on the seeds daily (quite evident from the topic, though) then you’re absolutely right. Check to see if there’s any sprouting so that you can uncover the containers and ensure there’s light being delivered to the seedlings; the moisture content should be just right because excessive wetness can cause premature death in crops. Check the growth of the seedlings; check your reservoir for a self-watering kit; check to assure the timer or lights are malfunctioning. 

As you start your seeding journey, build the habits. Do you remember to check the seeds daily? Are you making sure they’re constantly getting what they need? Keep a lookout for the weather. Don’t end up transplanting your plants outdoors too early just due to sheer excitement. There are countless stories of glum gardeners who did so and ended up with not-so-satisfying results. Safeguard your investment of attention and time by delaying the plantation rather than risking it by preponing it.  

At the very end, introduce your plants to the warm rays of the sun through a process known as “hardening off.” Keep them under the sun for an hour every day for one week. If they’re not sunbathing, set them in a protected location. Bring them inside if there’s frost at night. After about a week, they’ll be more or less used to the great outdoors and ready for transplantation. 


We hope our guide gave you somewhat of an idea about the perfect time to begin seeding indoors. Don’t be afraid to ask for help from other skilled neighbors; they may be your family members, friends, and most importantly, neighbors. Experiment and love the process; it’s very enjoyable if you don’t consider it a pressing burden.  

Find this content useful? Support us by checking out the affiliated links below:

Check out other popular electric gardening tools!

Electric Gardening Tools

I've been raised in a family of international gardeners spanning multiple generations, from vegetable growers in Germany to fruit tree growers in Iran. I hope you find the information you read useful to using electric gardening tools in gardening.

Recent Content